1. Field of the Invention
This invention relates to a suspension strut, or more particularly, to a suspension strut incorporating a pneumatic spring.
2. Disclosure Information
Suspension struts such as used in MacPherson type suspensions are commonly constructed with either coil springs or air springs mounted coaxially about the strut. A particular problem is encountered by front suspension struts which are mounted to the front steerable wheels. When the wheels are steered, the spring undergoes a twisting movement as the strut body turns with the wheel. The twisting undesirably changes the characteristics of the coil spring. To solve the torsional twist of coil springs, a bearing assembly is placed between the vehicle body and a mounted piston rod of the strut to allow the strut to rotate relative to the body. In this fashion, the twisting of the spring is avoided. U.S. Pat. No. 2,660,449 issued to MacPherson on Nov. 24, 1953 discloses such a bearing assembly.
Furthermore, U.S. Pat. No. 3,573,880 issued to Sakai on Apr. 6, 1971 discloses a coil spring rotatably mounted with respect to a strut housing by means of a ball joint introduced between a lower spring seat and the housing.
Air springs also are mounted about suspension struts alone or in combination with coil springs. U.S. Pat. No. 3,954,257 issued to Keijzer et al on May 4, 1976 discloses a strut having an air leveler in conjunction with a coil spring rotatably mounted through a bearing assembly to the vehicle body.
It is desirous when incorporating an air suspension spring on a MacPherson strut assembly to allow for replacement of the MacPherson strut without removal or disassembly of the air spring assembly. In order to do this, the air spring should be detachable with respect to the strut body. In doing so, it is desirous to place a bearing between the air spring assembly and the strut body.